/**
 * Copyright (c) 2006-2009 by Carnegie Mellon University and others.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *    1. Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *    2. Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *    3. Neither the names of the authors nor the
 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS ''AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
package edu.cmu.cs.plural.annot;

/**
 * This enumeration distinguishes the allowed uses of a permission:
 * <ul>
 * <li>Dynamic dispatch (only): {@link #DISPATCH}
 * <li>Field access (only): {@link #FIELDS}
 * <li>Both: {@link #DISP_FIELDS}
 * </ul>
 * This is primarily interesting to distinguish receiver permissions of
 * instance methods; permissions for other objects are usually (implicitly)
 * dispatch-only.
 * All permissions can be passed into private methods since these are
 * statically dispatched.
 * @author Kevin Bierhoff
 * @since Mar 25, 2009
 * @see Unique
 * @see Full
 * @see Share
 * @see Imm
 * @see Pure
 */
public enum Use {
	/** Dispatch-only use allows dynamic dispatch <b>but no field access</b>. */
	DISPATCH, 

	/** Fields-only use allows field access <b>but no dynamic dispatch</b>. */
	FIELDS,

	/** 
	 * Allows both dynamic dispatch and field access, but <b>if only one
	 * or the other is needed then that should be preferred</b> over this
	 * mode of use.
	 */
	DISP_FIELDS
}
